The 51-year-old was jailed in 2005 for multiple sex offences against children aged between five and 11.
He will be released next month.
The Parole Board says Capill has completed the Kia Marama Programme for sex offenders and would not be a high risk of reoffending if he was released early.
"The psychologist noted that Mr Capill had made progress in intellectually understanding his offending and the salient skills for managing his risk for reoffending,â€ť the decision reads.
"We further take into account that Mr Capill has presented well to the Board and it certainly is a contrast to his presentation three years ago."
Capill's released conditions include an order to refrain from contact with anyone under 16 unless he is given written consent from his probation officer.
Capill rose to become leader of the then-high profile Christian Heritage Party and campaigned on a Christian morals platform to get into Parliament. The party is now defunct but at its peak Capill was frequently quoted in the media espousing 'family values' which he claimed equal rights for glbt people would destroy.